Chern number, Hall response and edge index
Research context
postgraduate concept · conditional · As of 2026-10-10
For a gapped noninteracting two-dimensional band system, the occupied-band Berry curvature integrates to an integer C=(2π)⁻¹∫_BZTrF_xy d²k.
Key knowledge
For a gapped noninteracting two-dimensional band system, the occupied-band Berry curvature integrates to an integer C=(2π)⁻¹∫_BZTrF_xy d²k. Under the applicable insulating zero-temperature conditions, σ_xy=C e²/h. Interfaces carry net chiral edge modes set by the change in C; the invariant requires the separating gap to remain open.
Values and equations
C=(1/(2π))∫_BZTrF_xy d²k; σ_xy=C e²/h
- C
- Integer occupied-subspace Chern invariant
- F_xy
- Berry curvature for wavevector coordinates m²
- k
- Wavevector m⁻¹
- σ_xy
- Two-dimensional sheet Hall conductivity S
- e
- Charge magnitude C
- h
- Planck constant J s
Conditions and scope
- Periodic bulk model, specified filled bands and Berry convention; degeneracies within the occupied subspace require its matrix-valued connection.
- Interactions, disorder, finite temperature and dissipative contacts require appropriate generalizations or corrections. A computed toy invariant is not proof of a particular material's transport.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Inspected §§II.A–II.C and III: Berry connection, Chern integer, edge index, time reversal and measured surface signatures; source check dated 2026-10-10. Scope is limited to the cited statements, equations and assumptions, not the whole publication.
2026-10-10 · Author source inspection of the displayed claim, model assumptions and equations; independent exact-content and branch-inventory review is a separate gate. Contemporary status is a dated snapshot, not a promise of ongoing monitoring.
Entry details
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- research-physics-chern-hall-edge
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